As the vice president of innovation and technology for Enernex, an electric power research and consulting company, in Knoxville, Tenn., I have been asked repeatedly to predict whether there is a danger of blackouts when snowstorms hit various parts of the world in the coming months. Weather services have gone back and forth debating how cold these months will be, especially compared to the dramatic drop in temperature many experienced just last year.
That question is especially important for the electric industry. About a year ago, snowstorms brought parts of the northern United States to nearly the limit of its capacity in available power generation. On several of those days, utilities had to look for alternative energy sources and ask their customers to curtail their use of electricity. And on the worst days, prices went up from a normal cost of US $30 to $60 dollars per megawatt hour to more than $1,500 a MWH in the spot market, which is when a commodity or service is sold the same day for cash. This same concern also applies to the hottest days as well when there is a dire need for air conditioning and refrigeration.
To anticipate the demand and determine if there will be a shortage of electricity, utilities need to look to a number of factors, including:
- The size of the affected area. The larger the area, the more demand there will be. If there is a quick moving storm that covers an area of 500 to 800 kilometers, there most likely will not be a major problem with electricity supply. However, a storm anticipated to sweep through an entire region of a country is something to prepare for.
- The reliability of alternative sources. Large wind turbine systems can experience little wind on cold days. The Midwest Independent System Operator, based in Carmel, Ind., has 12 gigawatts of wind generation in installed capacity, but during the polar vortex that took place there in January, the wind generation created roughly 2 GW of power each hour. The same is true for solar. Due to fewer hours of sunlight, the fact that there are not enough solar plants installed in many areas, and that snow-covered solar cells produce little electricity, this is an insufficient source for generating power during winter storms.
- Frozen energy sources. On very cold days, piles of coal at generation facilities can freeze. Frozen coal piles require a lot of manpower to separate the pieces and move them into boilers, which can sometimes make the coal infeasible to use as a backup.
- Transportation concerns. Coal plants typically are filled prior to the anticipation of poor weather; however, sometimes storms hit before they are expected or coal simply runs out. The ability to transport coal during these times is not always practical. Moreover, power has to be used just to de-ice the train lines.
- Operational outages at utilities. If a power plant is running in very cold conditions at full power for a number of days, the stress on some components may lead to operational failures and major problems.
- Reliance on other utilities. Many homes in eastern Canada are heated by electricity that Quebec exports into the northeastern United States. But if Quebec itself needs more electricity due to its own storms, there may not be as much to export to other areas, if at all.
These challenges are important to pay attention to as the weather changes. Although utilities work hard to provide enough electrical capacity to not have to panic, there can always be potential, sometimes unforeseen, weather-related problems.
Many lessons were learned over the past year, and contingency plans have been developed. Some of the system operators are now tracking the pipeline capacity and the availability of natural gas to use during cold spells since it is becoming a larger source of fuel. Hydro-electric plants and storage units are being tracked more carefully as well. Many system operators are reviewing industrial demand response contractors to make sure they can call on them in extreme cold. Some utilities are also working with both commercial and industrial customers who have conventional backup generation so that they can call on them to use their alternate sources in order to free up energy for other users.
In the long term, better insulation in buildings and other energy efficiency measures will provide the best outlook for electricity needs during extreme cold. In fact, there are things we can all do to prepare, just in case.
Doug Houseman is an IEEE senior member. He is also a coauthor of the IEEE Grid Vision 2050 Roadmap.